Painter Bob Ross, whose 70th birthday is celebrated with a doodle on Google's home page, was famous for his soothing voice.

“We don't have mistakes here,” the host of the long-running PBS program, “The Joy of Painting,” would often say as he completed a landscape painting using oils. “We just have happy accidents.” When adding items, Ross often referred to them as “happy”: the artist would dab in a “happy little cloud” or a “happy little tree.”

What made the painter so softspoken? Ross said that he promised himself he would keep his voice down after his time in the military. The artist joined the Air Force when he was 19 and was sent to Alaska, the place where he saw daily the geographic features like mountains and snow that would feature heavily in his “Joy of Painting” artwork. (Ross was originally from Florida and then went to high school in Pennsylvania.) The artist started painting landscapes on tins used for gold-panning on his lunch breaks and sold them to gift shops to make extra cash while in the military.

But it was his job as first sergeant that made Ross promise himself to never scream again when he left the Air Force.

“I was the guy who makes you scrub the latrine, the guy who makes you make your bed, the guy who screams at you for being late to work,”' he told the Orlando Sentinel. “The job requires you to be a mean, tough person. And I was fed up with it. I promised myself that if I ever got away from it, it wasn't going to be that way any more.”

Ross started his public-access TV show in 1983, on which the artist was able to create a painting quickly by using the wet-on-wet oil technique. Wet-on-wet oil painting lets an artist add wet paint on top of a layer that is still wet and thus complete the artwork more quickly rather than requiring the painter to wait for one layer to dry.

Though the TV series ended in 1994, a year before Ross passed away, clips and full episodes of his shows on YouTube have individually racked up millions of hits, with one video titled “Bob Ross: Painting Mountains” boasting more than 4 million views.

“'I don't intimidate anyone,” Ross said in an interview with the Sentinel of his show. “Instead, I try to get people to believe in themselves. I tell people, 'You can do this.' And they write back and say, 'You were right. I can do this. And now I believe I can do anything.’”